A 29-year-old man presents with red, watery eyes for 4 days, starting in the right eye and spreading to the left. His 5-year-old daughter had a cold with red eyes last week. His eyes feel gritty and burn, with mild light sensitivity, but there is no severe pain and vision is unchanged. He wears no contact lenses. He has already bought antibiotic eye drops from a pharmacy, which have not helped.
Examination Findings
Visual acuity 6/6 both eyes. Bilateral conjunctival injection, right worse than left, with a watery discharge. Everted lids show follicles on the lower tarsal conjunctiva. A tender preauricular lymph node is palpable on the right. Fluorescein staining shows scattered punctate epithelial erosions; one week later, faint subepithelial infiltrates appear in the right cornea. Anterior chamber is quiet. Intraocular pressure normal.
Investigations
Diagnosis is clinical. Fluorescein staining excludes a dendritic ulcer (herpes simplex). Viral PCR is available in some settings but rarely needed; the clinical triad of follicles, watery discharge, and preauricular node is diagnostic.
Questions to Think About
- Which three clinical features point to a viral rather than bacterial cause?
- Why have the antibiotic drops not helped, and what should he be told?
- His vision blurs slightly in week 3 — what is happening, and how is it managed?
Diagnosis
Adenoviral conjunctivitis (epidemic keratoconjunctivitis spectrum) with early subepithelial infiltrates.
Reasoning
Reasoning: The sequential bilateral involvement after a sick contact, watery (not purulent) discharge, tarsal follicles, and a tender preauricular lymph node form the classic adenoviral conjunctivitis picture. The failure of antibiotic drops is expected — antibiotics do not act on viruses, and unnecessary antibiotics risk allergy and resistance. The week-3 visual blur with subepithelial infiltrates represents the immune response to viral antigen in the cornea; these infiltrates are typically self-limiting over weeks to months but can be visually significant. Diagnosis: adenoviral conjunctivitis (epidemic keratoconjunctivitis spectrum). Management: typical management is supportive and infection-control focused: preservative-free lubricants, cold compresses, and rigorous hygiene — hand washing, separate towels and pillowcases, no eye rubbing, and avoiding close contact while infectious (often 1–2 weeks). Patients are advised against sharing drops. Topical steroids are not routine; they are reserved for severe inflammation, pseudomembranes, or vision-threatening subepithelial infiltrates, prescribed and tapered by an eye specialist because steroids prolong viral shedding and risk pressure rise. Follow-up at 2–3 weeks checks for infiltrates and ensures resolution. He is counselled that the course is typically 2–4 weeks and that the late corneal haze usually clears.
Differential Diagnosis
- Bacterial conjunctivitis — ruled out: discharge is watery not purulent, follicles not papillae, and there is a tender preauricular node.
- Allergic conjunctivitis — ruled out: itching is mild, there is no seasonal pattern, and the preauricular node plus contact history favour viral.
- Herpes simplex keratitis — ruled out: no dendritic ulcer on fluorescein staining; adenoviral pseudomembranes and follicles differ from herpetic dendrites.
- Acute anterior uveitis — ruled out: no photophobia with ciliary flush, no cells and flare in the anterior chamber, vision preserved.
Management
Supportive care (lubricants, cold compresses); strict hygiene and isolation measures; no routine antibiotics; short supervised steroid course only for severe inflammation/pseudomembranes; follow-up for subepithelial infiltrates.
Key Learning Points
- Follicles + watery discharge + tender preauricular node = viral conjunctivitis until proven otherwise.
- Adenovirus is highly contagious — hand hygiene, separate towels, and avoiding eye rubbing are the core ‘treatment’.
- Antibiotics do not help viral conjunctivitis; topical steroids are reserved for severe cases (pseudomembranes, marked inflammation) under supervision.
- Subepithelial infiltrates typically appear in week 2–3 and can blur vision for weeks to months — warn the patient.
- Red flags needing escalation: severe pain, vision loss, dendritic ulcer, or anterior chamber inflammation.
Red Flags
- Severe eye pain or marked vision loss — think keratitis, uveitis, or acute glaucoma, not simple conjunctivitis.
- Dendritic fluorescein pattern — herpes simplex keratitis, needs antivirals not steroids.
- Pseudomembranes with bleeding on removal — severe adenoviral disease needing specialist care.
- Contact lens wear with pain — exclude microbial keratitis urgently.
Educational content only — not medical advice. Clinical decisions must be made by a qualified professional for the individual patient.
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